E. chromi is a collaboration between designers and scientists in the new field of synthetic biology. In 2009, seven Cambridge University undergraduates spent the summer genetically engineering bacteria to secrete a variety of coloured pigments, visible to the naked eye. They designed standardised sequences of DNA, known as BioBricks, and inserted them into E. coli bacteria.

Each BioBrick part contains genes selected from existing organisms spanning the living kingdoms, enabling the bacteria to produce a colour: red, yellow, green, blue, brown or violet. By combining these with other BioBricks, bacteria could be programmed to do useful things, such as indicate whether drinking water is safe by turning red if they sense a toxin.